// Copyright 2013 The Rust Project Developers. See the COPYRIGHT // file at the top-level directory of this distribution and at // http://rust-lang.org/COPYRIGHT. // // Licensed under the Apache License, Version 2.0 or the MIT license // , at your // option. This file may not be copied, modified, or distributed // except according to those terms. struct X { a: isize } trait Changer { fn change(self) -> Self; } impl Changer for X { fn change(mut self) -> X { self.a = 55; self } } pub fn main() { let x = X { a: 32 }; let new_x = x.change(); assert_eq!(new_x.a, 55); }